This invention relates to an improved metallic catalyst support and to a method of converting hydrocarbon waste gas streams to carbon dioxide and water which utilizes this improved metallic catalyst support.
Under modern pollution control regulations, many waste gas streams which contain minor amounts of hydrocarbons require final clean-up and at least substantial conversion to carbon dioxide and water before they can be released to the atmosphere. In particular, in the oxidation of ethylene to ethylene oxide, a by-product vent gas stream containing about 1% by volume of ethylene is removed from the reactor system. The ethylene contained in this waste stream is of too low a concentration to be recycled and is normally vented to the atmosphere. However, in many localities, the ethylene contained in this stream must be converted to carbon dioxide and water before being released. Similar problems are encountered with the naphtha based solvents which are used in a wide variety of applications.
One method that has been frequently used in the past to treat these waste gas streams is to pass them through a catalyst bed containing a catalytically active metal catalyst such as platinum, palladium or the like. While many different types of catalyst supports have been used for the catalytically active metals, a frequently used support is a crimped metal ribbon. While this type of packed catalyst bed is successful in converting a large percentage of the hydrocarbon in the waste gas to carbon dioxide and water, it falls short of total conversion. Accordingly, there is a need for catalysts and/or catalyst supports which will promote higher rates of conversion.